Yes, You Can Write Off That Sonoma Weekend — Here's How to Do It Right

Here's something a lot of Bay Area business owners don't realize: that weekend trip to Sonoma or Carmel can be a legitimate business deduction. Not a gray-area deduction. Not a "let's hope the IRS doesn't look at this" deduction. A real, defensible, IRS-compliant write-off — if you structure it correctly.

The key word is structure. The trip itself isn't magic. The business purpose is what makes it deductible. And there's a right way and a wrong way to do this.

The IRS Primary Purpose Test

The IRS uses one core question to evaluate any trip that mixes business and personal time: Was the primary purpose of this trip business, or personal?

If business dominates, your transportation costs are fully deductible — even if you spend part of the trip hiking through wine country or sitting on the beach in Carmel. If personal dominates, your transportation is nondeductible — though specific business expenses at the destination might still qualify.

There's no magic percentage, but the practical rule most tax professionals use is simple: business days need to outnumber personal days. Plan your trip around that math.

The IRS Topic 511 on business travel covers the basics. IRS Publication 463 is the full rulebook. The 2026 standard mileage rate is $0.725 per mile if you're driving yourself.

The Weekend Sandwich Rule — This Is Your Best Friend

Here's the part that makes a Friday-through-Monday trip extremely powerful from a tax standpoint.

Per IRS rules, if you have legitimate business activity on a Friday and additional legitimate business activity on the following Monday, the weekend in between — Saturday and Sunday — counts as business days. Even if you spend them entirely on personal activities.

The IRS reasoning is practical: it would often cost more to travel home and back than to just stay at the destination over the weekend. So those weekend days count.

A concrete example for a Bay Area business owner:

• Friday: Drive to Sonoma. Hold a formal board meeting or strategic planning session at your resort
• Saturday–Sunday: Enjoy the weekend — wine tasting, hiking, whatever you want
• Monday: Follow-up client meeting, site visit, or second board session before driving home

Result: All four days are business days. Your transportation, lodging, and 50% of your meals for the whole trip are deductible.

What's Actually Deductible

Once your trip qualifies as primarily business, here's what you can write off:

Transportation: Fully deductible. Gas mileage at $0.725/mile, or actual vehicle costs. If you rent a car, deduct the business-use portion.

Lodging: Fully deductible for business days. Keep your receipts — the IRS requires receipts for all lodging regardless of amount.

Meals: 50% deductible. You don't have to be discussing business at every meal — a solo dinner at the hotel qualifies as long as you're there for business. Baker Tilly's 2026 meals and travel deduction guide covers the current rules clearly.

What's not deductible: Entertainment, wine tasting tours, golf, shows, spa treatments, and anything personal in nature. Also, your spouse's expenses are not deductible unless they're a bona fide employee of your business with a legitimate business purpose for the trip.

What Makes the Business Activity Legitimate

This is where people get sloppy — and where the IRS looks first during an audit.

A "business meeting" that's really just dinner with a friend won't hold up. Here's what does:

• A formal board meeting with a written agenda and minutes documenting actual decisions made
• A strategic planning session with specific business outcomes documented
• Client meetings with clear business purpose
• Scouting a new business location (with documentation that you actually did this)
• An industry conference or professional development event

The documentation requirement is straightforward but non-negotiable. For every expense over $75 you need a receipt. For every business activity you need: the date, the location, who was there, and the specific business purpose. Create this documentation at the time — not months later when you're doing your taxes.

QuickBooks' business travel deduction guide and Expensify's 2026 self-employed travel guide both cover documentation best practices well.

The Numbers on a Typical Sonoma Trip

To make this concrete — here's what a four-day Sonoma trip might look like for an SF business owner:

• Mileage (SF to Sonoma, ~50 miles each way): ~$72
• Lodging (3 nights at ~$200/night): $600 fully deductible
• Meals (50% of ~$300 over 4 days): $150
• Total deduction: ~$822

At a combined federal + California marginal rate of around 40%, that's roughly $330 in actual tax savings from one trip. Not life-changing on its own, but add a couple of these per year and it adds up — and you're taking trips you'd be taking anyway.

One Thing to Watch in 2026

Starting January 1, 2026, employer-provided meals on business premises are no longer deductible under the OBBBA. This doesn't affect your travel meal deductions — those are still 50% deductible. But if you've been deducting company lunches and snacks at your SF office, that changed this year. Nolo's 2026 business meal deduction guide covers this distinction clearly.

Let Asnani CPA Help You Do This Right

The difference between a deductible business trip and an IRS problem is documentation and intent. We help San Francisco and Bay Area business owners set up tax planning and recordkeeping systems that make these deductions clean and defensible year after year.

If you want to make sure your business travel strategy is solid — or if you're wondering what else you might be missing — we'd love to have a conversation.

We work with business owners across San Francisco, Palo Alto, San Jose, Menlo Park, and throughout the Bay Area. Check out our post on Q4 tax strategies and year-round tax planning for more ideas.

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